U.S. patent application number 10/220155 was filed with the patent office on 2003-02-06 for method for producing chlorocarboxylic acid chlorides.
Invention is credited to Closs, Friedrich, Gotz, Roland, Henkelmann, Jochem, Kneuper, Heinz-Josef, Stamm, Armin.
Application Number | 20030028046 10/220155 |
Document ID | / |
Family ID | 26004686 |
Filed Date | 2003-02-06 |
United States Patent
Application |
20030028046 |
Kind Code |
A1 |
Stamm, Armin ; et
al. |
February 6, 2003 |
Method for producing chlorocarboxylic acid chlorides
Abstract
A process for the preparation of chlorocarboxylic chlorides of
formula (I) 1 in which R.sup.1 and R.sup.2 independently denote a
hydrogen atom, a carbon-containing organic radical, a halogen, or a
nitro or cyano group; and Y denotes an alkylene chain which
contains from 1 to 10 carbons in the chain and which is
unsubstituted or substituted by carbon-containing organic radicals,
halogen, nitro and/or cyano groups, and the alkylene chain can be
interrupted by an ether, thioether, tertiary amino or keto group,
and the carbon-containing organic radicals of Y and/or R.sup.1
and/or R.sup.2 can be bonded to each other so as to form a
non-aromatic system, by reaction of a lactone of formula (II) 2 in
which R.sup.1, R.sup.2 and Y have the meanings stated above, with a
chlorinating agent in the presence of a chlorinating catalyst, in
which the reaction is carried out in the presence of a boron
compound.
Inventors: |
Stamm, Armin; (Nieder-Olm,
DE) ; Gotz, Roland; (Neulussheim, DE) ;
Henkelmann, Jochem; (Mannheim, DE) ; Closs,
Friedrich; (Mannheim, DE) ; Kneuper, Heinz-Josef;
(Niederkirchen, DE) |
Correspondence
Address: |
KEIL & WEINKAUF
1350 CONNECTICUT AVENUE, N.W.
WASHINGTON
DC
20036
US
|
Family ID: |
26004686 |
Appl. No.: |
10/220155 |
Filed: |
August 27, 2002 |
PCT Filed: |
February 28, 2001 |
PCT NO: |
PCT/EP01/02238 |
Current U.S.
Class: |
558/440 ;
562/857 |
Current CPC
Class: |
C07C 51/60 20130101;
C07C 51/60 20130101; C07C 53/50 20130101 |
Class at
Publication: |
558/440 ;
562/857 |
International
Class: |
C07C 051/58 |
Claims
We claim:
1. A process for preparing chlorocarbonyl chlorides of the formula
(I) 12in which R.sup.1 and R.sup.2 independently of one another are
a hydrogen atom, a carbon-containing organic radical, a halogen, a
nitro or a cyano group, and Y is an alkylene chain having 1 to 10
carbon atoms in the chain, which is unsubstituted or substituted by
carbon-containing organic radicals, halogen, nitro and/or cyano
groups, where the alkylene chain may be interrupted by an ether, a
thioether, a tertiary amino or a keto group, where the
carbon-containing organic radicals of Y and/or R.sup.1 and/or
R.sup.2 may be attached to one another forming a nonaromatic
system, by reacting a lactone of the formula (ii) 13in which
R.sup.1, R.sup.2 and Y are as defined above, with a chlorinating
agent in the presence of a chlorination catalyst, which comprises
carrying out the reaction in the presence of boron oxide, oxoboric
acids, salts of the oxoboric acids or mixtures thereof.
2. A process as claimed in claim 1, wherein boric acid is used.
3. A process as claimed in claim 1 or 2, wherein the boron compound
is employed in a concentration of 0.1-20 mol %, based on the
lactone (II).
4. A process as claimed in any of claims 1 to 3, wherein the
chlorinating agent used is phosgene, diphosgene, triphosgene or
thionyl chloride.
5. A process as claimed in any of claims 1 to 4, wherein the
chlorination catalyst used is a urea compound, a phosphine oxide, a
pyridinium compound or a mixture thereof.
6. A process as claimed in claim 5, wherein the chlorination
catalyst used is 3-methylpyridine, triphenylphosphine oxide and/or
trialkylphosphine oxide.
7. A process as claimed in any of claims 1 to 6, wherein the
chlorination catalyst is employed in a concentration of from 0.1 to
20 mol %, based on the lactone (II).
8. A process as claimed in any of claims 1 to 7, wherein the
chlorination catalyst and the boron compound are employed in the
form of a complex of the two components.
9. A process as claimed in any of claims 1 to 8, wherein the
reaction is carried out at a temperature of 50-200.degree. C. and
an absolute pressure of 0.01-5 MPa.
10. A process as claimed in any of claims 1 to 9, wherein the
lactone (II) used is .gamma.-butyrolactone, .delta.-valerolactone
or .epsilon.-caprolactone.
Description
DESCRIPTION
[0001] The present invention relates to a process for the
preparation of chlorocarboxylic chlorides of formula (I) 3
[0002] in which
[0003] R.sup.1 and R.sup.2 independently denote
[0004] a hydrogen atom, a carbon-containing organic radical, a
halogen, or a nitro or cyano group;
[0005] and Y denotes
[0006] an alkylene chain which contains from 1 to 10 carbons in the
chain and which is unsubstituted or substituted by
carbon-containing organic radicals, halogen, nitro and/or cyano
groups, and the alkylene chain can be interrupted by an ether,
thioether, tertiary amino or keto group,
[0007] and the carbon-containing organic radicals of Y and/or
R.sup.1 and/or R.sup.2 can be bonded to each other so as to form a
non-aromatic system,
[0008] by reaction of a lactone of formula (II) 4
[0009] in which R.sup.1 and R.sup.2 and Y have the meanings stated
above, with a chlorinating agent in the presence of a chlorinating
catalyst.
[0010] Chlorocarboxylic chlorides are important reactive
intermediate products for the preparation of pharmaceutical and
agrochemical active substances.
[0011] Chlorocarboxylic chlorides can be prepared, for example, by
reaction of the corresponding lactones with chlorinating agents in
the presence of a catalyst. The chlorinating agents used are
typically phosgene or thionyl chloride, since they form, as
coupling products, exclusively gaseous substances (CO.sub.2 or
SO.sub.2 and HCl).
[0012] When use is made of thionyl chloride as chlorinating agent
zinc chloride is usually employed as catalyst. Appropriate
processes are described in I. I. Grandberg et.al, Izv.
Timiryazevsk. S.kh. Akad. 1974, (6), pages 198 to 204 and O. P.
Goel et. al., Synthesis, 1973, pages 538 to 539. The conversion of
.gamma.-butyrolactone to 4-chlorobutyric chloride gave yields of
from 65 to 80%.
[0013] When use is made of phosgene as chlorinating agent various
catalyst systems are generally used. U.S. Pat. No. 2,778,852
mentions the following as being suitable catalysts: pyridines,
tertiary amines, heavy metals and acids, such as sulfuric acid,
phosphoric acid, phosphorus chloride, phosphorus oxychloride,
aluminum chloride, sulfuryl chloride and chlorosulfuric acid.
Suitable catalysts are, according to laid-open specification DE-A
19,753,773, urea compounds, according to laid-open specifications
EP-A 0,413,264 and EP-A 0,435,714, phosphine oxides, and according
to laid-open specifications EP-A 0,253,214 and EP-A 0,583,589,
organonitrogen compounds such as quaternary ammonium salts,
heterocyclic nitrogen compounds, amines or formamides.
[0014] U.S. Pat. No. 2,778,852 describes the synthesis of
4-chlorobutyric chloride by reaction of .gamma.-butyrolactone with
phosgene in the presence of pyridine.
[0015] In order to increase the yield, hydrogen chloride gas is
usually additionally introduced. The use of hydrogen chloride is
however disadvantageous, particularly for ecological and economical
reasons, since it is used in hyperstoichiometric amounts and the
excess portion must be purified and neutralized, which leads to
considerable accumulation of salt. Furthermore, the use of large
amounts of hydrogen chloride gas must meet additional technological
and logistic requirements.
[0016] The object of the present invention is thus to provide a
process for the preparation of chlorocarboxylic chlorides by
reaction of the corresponding lactones with chlorinating agents,
which process no longer suffers from the known drawbacks and
produces the chlorocarboxylic chlorides in a high yield and high
state of purity.
[0017] Accordingly, we have found a process for the preparation of
chlorocarboxylic chlorides of formula (I) 5
[0018] in which
[0019] R.sup.1 and R.sup.2 independently denote
[0020] a hydrogen atom, a carbon-containing organic radical, a
halogen, or a nitro or cyano group;
[0021] and Y denotes
[0022] an alkylene chain which contains from 1 to 10 carbons in the
chain and which is unsubstituted or substituted by
carbon-containing organic radicals, halogen, nitro and/or cyano
groups, and the alkylene chain can be interrupted by an ether,
thioether, tertiary amino or keto group,
[0023] and the carbon-containing organic radicals of Y and/or
R.sup.1 and/or R.sup.2 can be bonded to each other so as to form a
non-aromatic system,
[0024] by reaction of a lactone of formula (II) 6
[0025] in which R.sup.1, R.sup.2 and Y have the meanings stated
above, with a chlorinating agent in the presence of a chlorinating
catalyst, which is characterized in that conversion is carried out
in the presence of a boron compound.
[0026] An essential feature of the process of the invention is the
presence of a boron compound. Examples of suitable boron compounds
are the compounds and groups of substances listed below, mixtures
of different boron compounds being likewise possible:
[0027] boron oxide, such as B.sub.2O.sub.3;
[0028] boric oxy acids, such as boric acid (H.sub.3BO.sub.3, more
correctly: "orthoboric acid"), metaboric acids (of the type
HBO.sub.2, eg .alpha.-HBO.sub.2, .beta.-HBO.sub.2 or
.gamma.-HBO.sub.2), oligoboric acids or polyboric acids;
[0029] salts of boric oxy acids, such as borates
([BO.sub.3].sup.3-, more correctly: "orthoborate"), oligoborates
(eg [B.sub.3O.sub.3 (OH).sub.5].sup.2-,
[B.sub.4O.sub.5(OH).sub.4].sup.2-,
[B.sub.5O.sub.6(OH).sub.6].sup.3- or
[B.sub.6O.sub.7(OH).sub.6].sup.2-) or polyborates (eg
[BO.sub.2].sup.-) with inorganic or organic cations, for example
alkali metal ions (eg Li.sup.+, Na.sup.+ or K.sup.+), alkaline
earth metal ions (eg Mg.sup.2+, Ca.sup.2+ or Sr.sup.2+), the
ammonium ion NH.sub.4.sup.+ or primary, secondary, tertiary or
quaternary amines (eg tetramethylammonium, tetraethylammonium,
tetrapropylammonium, tetraisopropylammonium,
phenyltrimethylammonium, phenyltriethylammonium, trimethylammonium,
triethylammonium, tripropylammonium, triisopropylammonium,
phenyldimethylammonium, phenyldiethylammonium or phenylammonium
("anilinium"));
[0030] boronic acids (R--B(OH).sub.2) and their inorganic or
organic salts, such as benzeneboronic acid (dihydroxyphenylborane)
or disodium phenyl boronate;
[0031] boric acid esters, such as the mono-, di- or
tri-(C.sub.1-C.sub.6 alkyl) esters having the same or different,
unbranched or branched alkyl groups (eg methyl, ethyl, propyl,
1-methylethyl, butyl, 1-methylpropyl, 2-methylpropyl,
1,1-dimethylethyl, pentyl, 1-methylbutyl, 2-methylbutyl,
3-methylbutyl, 2,2-dimethylpropyl, 1-ethylpropyl, hexyl,
1,1-dimethylpropyl, 1,2-dimethylpropyl, 1-methylpentyl,
2-methylpentyl, 3-methylpentyl, 4-methylpentyl, 1,1-dimethylbutyl,
1,2-dimethylbutyl, 1,3-dimethylbutyl, 2,2-dimethylbutyl,
2,3-dimethylbutyl, 3,3-dimethylbutyl, 1-ethylbutyl, 2-ethylbutyl,
1,1,2-trimethylpropyl, 1,2,2-trimethylpropyl,
1-ethyl-l-methylpropyl or 1-ethyl-2-methylpropyl), for example
trimethyl borate, triethyl borate or tripropyl borate;
[0032] boron halides containing fluorine, chlorine, bromine and/or
iodine, for example BF.sub.3 (boron trifluoride), BC1.sub.3 (boron
trichloride), BBr.sub.3 (boron tribromide), BI.sub.3 (boron
triiodide), BF.sub.2Cl, BFCl.sub.2, BF.sub.2Br, BFBr.sub.2,
BF.sub.2I, BFI.sub.2, BFClBr, BFClI, BFBrI, BCl.sub.2Br,
BClBr.sub.2, BCl.sub.2I, BClI.sub.2, BClBrI, BBr.sub.2I,
BBrI.sub.2, B.sub.2F.sub.4, B.sub.2Cl.sub.4, B.sub.2Br.sub.4,
B.sub.2I.sub.4 and their complexes, for example with oxygen, sulfur
or nitrogen compounds, such as hydrates, alkoxides, etherates,
complexes with sulfides, ammonia, amines or pyridines, for example
[water.BF.sub.3], [methanol.BF.sub.3], [ethanol.BF.sub.3],
[dimethyl ether.BF.sub.3], [diethyl ether.BF.sub.3], [n-propyl
ether.BF.sub.3], [diisopropyl ether.BF.sub.3],
[tetrahydrofuran.BF.sub.3], [dimethyl sulfide.BF.sub.3],
[ammonia.BF.sub.3], [methylamine.BF.sub.3],
[dimethylamine.BF.sub.3], [trimethylamine.BF.sub.3],
[ethylamine.BF.sub.3], [diethylamine.BF.sub.3],
[triethylamine.BF.sub.3], [urea.BF.sub.3], [pyridine.BF.sub.3],
[2-methylpyridine.BF.sub.3] or [3-methylpyridine.BF.sub.3].
[0033] The compounds preferably used are
[0034] boron oxide B.sub.2O.sub.3;
[0035] boric acid H.sub.3BO.sub.3;
[0036] tri(C.sub.3-C.sub.4 alkyl) borates, such as trimethyl
borate, triethyl borate, tripropyl borate, triisopropyl borate or
tributyl borate;
[0037] boron trifluoride, boron trichloride or their complexes, for
example with water, alcohols (particularly methanol), ethers
(particularly diethyl ether), sulfides (particularly dimethyl
sulfide) or amines (particularly ethylamine), for example boron
trifluoride dihydrate or boron trifluoride etherates (particularly
with diethyl ether);
[0038] or mixtures thereof.
[0039] Very preferably used are the halogen-free boron compounds
boron oxide B.sub.2O.sub.3, boric acid H.sub.3BO.sub.3 and
tri(C.sub.1-C.sub.4 alkyl) borate. Particularly preferred are boric
acid H.sub.3BO.sub.3 and trimethyl borate. The use of such boron
compounds has the advantage that the reaction mixtures are free
from fluoride ions. This simplifies the entire apparatus technology
as against the reaction involving boron halides.
[0040] In the process of the invention the boron compound or
mixture thereof is used in a concentration of from 0.1 to 20 mol %,
preferably from 0.1 to 10 mol % and more preferably from 0.5 to 5
mol % based on the lactone (II).
[0041] The chlorocarboxylic chlorides produced by the process of
the invention conform to formula (I) 7
[0042] in which R.sup.1 and R.sup.2 independently denote a hydrogen
atom, a carbon-containing organic radical, a halogen or a nitro or
cyano group.
[0043] By a carbon-containing organic radical we mean an
unsubstituted or substituted, aliphatic, aromatic or araliphatic
radical containing from 1 to 20 carbons. This radical can contain
one or more heteroatoms, such as oxygen, nitrogen or sulfur, for
example --O--, --S--, --NR--, --CO-- and/or --N.dbd. in aliphatic
or aromatic systems, and/or may be substituted by one or more
functional groups containing, for example, oxygen, nitrogen, sulfur
and/or halogen, for example substituted by fluorine, chlorine,
bromine, iodine and/or cyano. If the carbon-containing organic
radical contains one or more heteroatoms, it may be bonded via a
heteroatom. Thus ether, thioether and tertiary amino groups are for
example also enclosed. As preferred examples of the
carbon-containing organic radical there may be mentioned
C.sub.1-C.sub.20 alkyl, particularly C.sub.1-C.sub.6 alkyl,
C.sub.6-C.sub.10 aryl, C.sub.7-C.sub.20 aralkyl, particularly
C.sub.7-C.sub.10 aralkyl, and C.sub.7-C.sub.20 alkaryl,
particularly C.sub.7-C.sub.10 alkaryl.
[0044] As examples of halogens there may be mentioned fluorine,
chlorine, bromine and iodine.
[0045] Preference is given to chlorocarboxylic chlorides (I) in
which R.sup.1 and R.sup.2 independently denote hydrogen,
C.sub.1-C.sub.6 alkyl, C.sub.6-C.sub.10 aryl, C.sub.7-C.sub.10
aralkyl or C.sub.7-C.sub.10 alkaryl, for example methyl, ethyl,
propyl, 1-methylethyl, butyl, 1-methylpropyl, 2-methylpropyl,
1,1-dimethylethyl, pentyl, 1-methylbutyl, 2-methylbutyl,
3-methylbutyl, 2,2-dimethylpropyl, 1-ethylpropyl, hexyl,
1,1-dimethylpropyl, 1,2-dimethylpropyl, 1-methylpentyl,
2-methylpentyl, 3-methylpentyl, 4-methylpentyl, 1,1-dimethylbutyl,
1,2-dimethylbutyl, 1,3-dimethylbutyl, 2,2-dimethylbutyl,
2,3-dimethylbutyl, 3,3-dimethylbutyl, 1-ethylbutyl, 2-ethylbutyl,
1,1,2-trimethylpropyl, 1,2,2-trimethylpropyl,
1-ethyl-1-methylpropyl, 1-ethyl-2-methylpropyl, phenyl,
2-methylphenyl (o-toluoyl), 3-methylphenyl (m-toluoyl),
4-methylphenyl (p-toluoyl), naphthyl or benzyl. Special preference
is given to hydrogen and C.sub.1-C.sub.4 alkyl, particularly
hydrogen.
[0046] Y denotes an alkylene chain having from 1 to 10 carbons in
the chain which may be unsubstituted or substituted by
carbon-containing organic radicals, halogen, nitro and/or cyano
groups, and the alkylene chain can be interrupted by an
ether(--O--), thioether(--S--), tertiaere amino(--NR--) or
keto(--CO--) group. The carbon-containing organic radicals and
halogen are as defined above.
[0047] As examples of the radical Y there may be mentioned the
alkenes (CH.sub.2).sub.n, in which n is equal to from 1 to 10 and
in which one or more or possibly all of the hydrogen atoms can be
replaced by C.sub.1-C.sub.6 alkyl, C.sub.6-C.sub.10 aryl,
C.sub.7-C.sub.10 aralkyl and/or C.sub.7-C.sub.10 alkaryl, for
example methyl, ethyl, propyl, 1-methylethyl, butyl,
1-methylpropyl, 2-methylpropyl, 1,1-dimethylethyl, pentyl,
1-methylbutyl, 2-methylbutyl, 3-methylbutyl, 2,2-dimethylpropyl,
1-ethylpropyl, hexyl, 1,1-dimethylpropyl, 1,2-dimethylpropyl,
1-methylpentyl, 2-methylpentyl, 3-methylpentyl, 4-methylpentyl,
1,1-dimethylbutyl, 1,2-dimethylbutyl, 1,3-dimethylbutyl,
2,2-dimethylbutyl, 2,3-dimethylbutyl, 3,3-dimethylbutyl,
1-ethylbutyl, 2-ethylbutyl, 1,1,2-trimethylpropyl,
1,2,2-trimethylpropyl, 1-ethyl-l-methylpropyl,
1-ethyl-2-methylpropyl, phenyl, 2-methylphenyl (o-toluoyl),
3-methylphenyl (m-toluoyl), 4-methylphenyl (p-toluoyl), naphthyl or
benzyl.
[0048] Preference is given to chlorocarboxylic chlorides (I) in
which Y denotes an unsubstituted alkene (CH.sub.2).sub.n in which n
is equal to from 2 to 8, preferably from 2 to 4, such as
CH.sub.2CH.sub.2, CH.sub.2CH.sub.2CH.sub.2 and
CH.sub.2CH.sub.2CH.sub.2CH.sub.2.
[0049] Possibly, the organic radicals R.sup.1 and/or R.sup.2 and/or
those of Y are bonded to each other to form a non-aromatic system.
As an example thereof there may be mentioned
hexahydrophthalide.
[0050] The chlorocarboxylic chlorides (I) that are greatly
preferred as products of the process of the invention are
4-chlorobutyric chloride (4-chlorobutanoic chloride),
5-chlorovaleric chloride (5-chloropentanoic chloride) or
6-chlorocaproic chloride (6-chlorohexanoic chloride).
[0051] The lactones to be used conform to formula (II) 8
[0052] in which R.sup.1, R.sup.2 and Y have the meanings stated
above. Of course, mixtures of different lactones can be used if
desired. We very much prefer to use .gamma.-butyrolactone,
.delta.-valerolactone or .epsilon.-caprolactone.
[0053] The chlorinating agents used are preferably phosgene,
diphosgene (trichloromethyl chloroformate), triphosgene
(bis(trichloromethyl)carbona- te) and/or thionyl chloride.
Particularly preferred is the use of phosgene or thionyl chloride,
particularly gaseous and/or liquid phosgene.
[0054] Suitable chlorinating catalysts are theoretically all known
chlorinating catalysts, particularly nitrogen and phosphorus
compounds, such as open-chain or cyclic, unsubstituted or
substituted ureas, di-N,N-substituted formamides (eg
N,N-dimethylformamide), trialkyl phosphine oxides or unsubstituted
or substituted triarylphosphine oxides, substituted or
unsubstituted pyridines, quaternary ammonium salts (eg
benzyltrimethylammonium chloride), amidines or salts thereof
including hydrochlorides, unsubstituted or mono- or
poly-N-substituted guanidines or hexaalkylguanidinium salts.
[0055] The chlorinating catalyst used is preferably a urea
compound, a phosphine oxide, a pyridine compound or a mixture
thereof.
[0056] The urea compounds that are preferably used are described,
for example, in laid-open specification DE-A 19,753,773. We
particularly prefer to use open-chain, substituted urea compounds
of formula (III) 9
[0057] in which X stands for oxygen or sulfur and R.sup.3 to
R.sup.2 independently denote preferably C.sub.1-C.sub.10 alkyl or
in which one of the radicals R.sup.3 or R.sup.2 forms, together
with one of the radicals R.sup.5 or R.sup.2, a C.sub.2-C.sub.4
alkylene chain. Very special preference is given to urea compounds
which are liquid under the conditions of the reaction, for example
N,N'-dimethylethylene urea (1,3-dimethyl-2-imidazolidinone),
N,N'-dimethylpropylene urea
(1,3-dimethyltetrahydro-2(1H)-pyrimidinone), N,N,N',N'-tetrabutyl
urea or N,N,N',N'-tetramethylthio urea. The said urea compounds can
be used as such or in the form of their salts with hydrochloric
acid, for example as hydrochlorides, or in the form of their
Vilsmeier-type salts as can be obtained by reaction with phosgene,
but the hydrochlorides are preferred.
[0058] The phosphine oxides that are preferably used are described,
for example, in laid-open specification EP-A 0,413,264. We
particularly prefer to use the trialkyl phosphine oxides or
unsubstituted or substituted triarylphosphine oxides of formula
(IV) 10
[0059] in which R.sup.7 to R.sup.9 independently denote preferably
C.sub.1-C.sub.10 alkyl or unsubstituted or (C.sub.1-C.sub.4
alkyl)-substituted phenyl. Very special preference is given to
phosphine oxides which are liquid under the conditions of the
reaction, for example linear or branched trioctyl, trihexyl or
tributyl phosphine oxides and also triphenylphosphine oxide or
mixtures of different trialkyl phosphine oxides (eg Cyanex sold by
Cytec Industries).
[0060] The substituted or unsubstituted pyridines that are
preferably used are represented by formula (V) 11
[0061] in which R.sup.10 to R.sup.14 independently denote
preferably hydrogen or C.sub.1-C.sub.4 alkyl. Another possibility
is that two adjacent radicals may be bonded to each other to form a
non-aromatic or aromatic system. Special preference is given to the
mono(C.sub.1-C.sub.4 alkyl)pyridines and most preferably the
monomethylpyridines, particularly 3-methylpyridine
(.beta.-picoline).
[0062] In the process of the invention, particularly
3-methylpyridine, triphenylphosphine oxide and/or trialkyl
phosphine oxide are used.
[0063] The use of liquid chlorinating catalysts has primarily
process engineering advantages. For example, there is no
complicated handling of solids and metering and transport thereof.
Furthermore substantially less viscous bottoms are obtain in the
following workup distillation stage and choking is avoided.
[0064] The chlorinating catalyst is used, in the process of the
invention, in a concentration of from 0.1 to 20 mol %, preferably
from 0.1 to 10 mol % and more preferably from 0.5 to 5 mol % based
on the lactone (II).
[0065] In another preferred embodiment of the process, the catalyst
is used in the form of a complex of the boron compound and the
chlorinating catalyst. This can be prepared, for example, by
admixture of the two components upstream of or in the reactor. An
example of a suitable complex is the BF.sub.3-.beta.-picoline
complex.
[0066] The reactors used for the chlorination can be,
theoretically, any apparatus for vapor-liquid or liquid-liquid
reactions described in the relevant technical literature. To
achieve a high space-time yield, it is important to effect intense
intermixture between the lactone, the solution containing the
chlorinating catalyst and the boron compound, and the added
chlorinating agent. As non-restrictive examples there may be
mentioned agitated tanks, cascades of stirred-tank reactors,
countercurrent reaction columns, flow tubes (preferably fitted with
baffles), bubble columns and loop reactors.
[0067] The process is preferably carried out without the use of
solvent. It is possible, however, to add a solvent that is inert to
the chlorinating agent used. Inert solvents are for example
aromatic hydrocarbons, such as toluene, chlorobenzene, o-, m- or
p-dichlorobenzene, o-, m- or p-xylene, cyclic carbonates, such as
ethylene carbonate or propylene carbonate, the same
chlorocarboxylic acid chloride as that to be produced or mixtures
thereof. If solvents are used, preferably the same chlorocarboxylic
acid chloride as that to be produced is used. The addition of a
solvent can be of advantage for example when use is made of
lactones (II) that are high-molecular, have a high-viscosity or are
solid under the conditions of the reaction.
[0068] The process of the invention can be carried out at a
temperature of from 50.degree. to 200.degree. C., preferably from
80.degree. to 200.degree. C., and more preferably from 110.degree.
to 160.degree. C. It is generally carried out under a pressure of
from 0.01 to 5 MPa absolute, preferably under a pressure of from
0.5 to 2 MPa absolute and more preferably under atmospheric
pressure.
[0069] The total amount of phosgene that is introduced in the
process of the invention is generally from 0.8 to 1.5 mol and
preferably from 0.9 to 1.2 mol per mol of lactone (II).
[0070] Addition of the educts (lactone (II) and chlorinating agent)
and the catalysts (chlorinating catalyst and boron compound) can
generally take place in any order. Preferably, in one variant, the
lactone (II), the chlorinating catalyst, the boron compound and
optionally a solvent are used as initial batch and the chlorinating
agent is then introduced or in another variant, all components are
introduced concurrently. Embodiments lying between these two
variants are of course possible and may be advantageous.
[0071] When adding the educts and catalysts it is possible to bring
the various components into contact with each other either upstream
of or in the reactor, as desired. Thus it is possible, for example,
to effect previous formation of a complex of the boron compound and
the chlorinating catalyst (eg the BF.sub.3-.beta.-picoline
complex). Furthermore it is possible to cause previous reaction
between the chlorinating catalyst and the chlorinating agent (eg
Vilsmeier salt of N,N-dialkyl formamide and phosgene or thionyl
chloride).
[0072] The process of the invention can be carried out batchwise or
continuously.
[0073] a) Batchwise Mode
[0074] When manufacturing in batchwise mode, the reaction mixture
containing the lactone (II), the chlorinating catalyst, the boron
compound and optionally a solvent is generally placed in a reactor,
for example an agitated tank, as the initial batch and mixed
intensely. Then the desired amount of liquid or gaseous
chlorinating agent is added at the desired temperature and
pressure. After adding the chlorinating agent the reaction solution
is allowed to continue reacting over a period ranging from a few
minutes to a few hours. This subsequent reaction can take place in
the reactor or in a vessel down-stream thereof.
[0075] In a special variant of the batchwise mode the liquid
chlorinating agent (eg thionyl chloride) can be used as initial
batch, optionally together with the chlorinating catalyst and/or
the boron compound and/or a solvent. The lactone (II) is then,
optionally together with the chlorinating catalyst and/or the boron
compound and/or a solvent, added at the desired temperature and
pressure over a given period of time.
[0076] b) Continuous Mode
[0077] Reactors that are suitable for the continuous process are
for example stirred tanks, cascades of stirred-tank reactors or
counter-current reaction towers. On starting the continuous process
generally a solvent (eg the same chlorocarboxylic acid chloride as
that to be produced), the chlorinating catalyst and the boron
compound are placed in the reactor and the system is heated to the
desired temperature, after which the liquid or gaseous chlorinating
agent is added. Then, parallel to the continuous feed of
chlorinating agent, there is started a continuous introduction of
lactone (II), which generally contains further chlorinating
catalyst and further boron compound and is optionally dissolved in
a solvent. After the reactor contents have been converted to
chlorocarboxylic chloride, the feed rates of lactone (II) and the
chlorinating agent are adjusted such that both of these components
are introduced in substantially equimolar amounts. Reaction mixture
is removed from the reactor, for example through a riser or
overflow, at a rate corresponding to the feed rate. Preferably, the
reaction solution is fed to another vessel for further
reaction.
[0078] It is then generally advantageous to expel ("strip")
unconverted chlorinating agent from the reaction solution, for
example by passing in a gas which is chemically inert to the
reaction solution, such as nitrogen.
[0079] Unconverted chlorinating agent which for example escapes
from the reactor during the synthesis stage and/or is expelled by
subsequent stripping, can advantageously be collected and reused.
Suitable receivers are for example cold traps, in which the
chlorinating agent condenses.
[0080] The reaction solution leaving the reaction of lactone (II)
and the chlorinating agent can be worked up by conventional
methods. Preference is given to purification by distillation,
optional stripping being carried out upstream of or in the
distillation column.
[0081] It is possible and may be advantageous to partially or
completely recycle the bottoms obtained from purification by
distillation and containing, inter alia, the chlorinating catalyst
and the boron compound. Of course, another workup of the bottoms,
for example distillation, to separate the chlorinating catalyst
and/or the boron compound, can take place prior to said recycling
operation. If the process is carried out with recycling of the
chlorinating catalyst and/or boron compound, it is of advantage to
recycle only a portion thereof, for the removal of possible
by-products, and to replace the other portion by fresh
catalysts.
[0082] In a general embodiment of the batchwise synthesis of
chlorocarboxylic chlorides (I), all of the appropriate lactone
(II), the (preferably liquid) chlorinating catalyst, the boron
compound and, optionally, a solvent (eg the same chlorocarboxylic
acid chloride as that to be produced) are placed in a stirred tank.
The reaction system is then heated to the desired temperature and
liquid and/or gaseous phosgene or liquid thionyl chloride is
introduced continuously under ambient pressure with continued
vigorous agitation. The resulting gaseous coupling products carbon
dioxide or sulfur dioxide and also hydrogen chloride are removed.
After the desired amount of chlorinating agent has been fed in, the
reaction solution is left for a while at the controlled
temperature, with continued agitation, for further reaction. During
this subsequent reaction, chlorinating agent still present in the
reaction solution reacts with the remaining lactone (II). In order
to strip all or some of the excess chlorinating agent and its
reaction products carbon dioxide or sulfur dioxide and hydrogen
chloride, from the reaction solution, it is possible to pass
through inert gas, with vigorous stirring. The resulting reaction
solution is then passed on to the workup stage. Generally, workup
is carried out by distillation, optionally in vacuo. In the case of
high-molecular chlorocarboxylic chlorides, other purifying
processes are possible, such as crystallization.
[0083] In a general embodiment for the continuous preparation of
chlorocarboxylic chlorides (I) a solvent (eg the same
chlorocarboxylic acid chloride as that to be produced), the
chlorinating catalyst and the boron compound are placed in the
reactor, eg a stirred tank, and the system is heated to the desired
temperature and liquid or gaseous chlorinating agent is added.
Then, parallel to the continuous feed of chlorinating agent, there
is started a continuous introduction of lactone (II), which
generally contains further chlorinating catalyst and further boron
compound and is optionally dissolved in a solvent. After the
reactor contents have been converted to chlorocarboxylic chloride,
the feed rates of lactone (II) and the chlorinating agent are
adjusted such that both of these components are introduced in
substantially equimolar amounts. Reaction mixture is removed from
the reactor, for example through a riser or overflow, at a rate
corresponding to the feed rate. The removed reaction solution is
collected in a vessel down-stream of the reactor, for example a
stirred tank, for subsequent reaction. When the said downstream
vessel is filled with said effluent, the overflow is optionally
freed from the coupling products carbon dioxide and hydrogen
chloride as described above and then passed on for workup. Workup
can be carried out by distillation, for example.
[0084] The process of the invention allows for the preparation of
chlorocarboxylic chlorides by reaction of the corresponding
lactones with a chlorinating agent, and produces the
chlorocarboxylic chlorides in a high yield and high state of purity
and no longer suffers from the drawback of having to additionally
feed in hydrogen chloride gas. During workup, the chlorocarboxylic
chlorides can be readily separated from the boron compounds added
in accordance with the invention.
EXAMPLES
[0085] Experimental Setup
[0086] The experimental setup comprises a glass vessel having a
capacity of 1L and equipped with a double-walled jacket and a
stirrer, thermostatic control means, an inlet pipe for the gaseous
or liquid chlorinating agent and a two-membered cascade of
condensers. The two-membered cascade of condensers comprises a
jacketed coil condenser, which is kept at -10.degree. C., and a
carbon dioxide condenser, which is kept at -78.degree. C. The
experiments were carried out under ambient pressure.
Example 1 (Invention)
[0087] 200 g (2.0 mol) of .delta.-valerolactone, 9.3 g (0.1 mol) of
.beta.-picoline (3-methylpyridine) and 3.1 g (0.05 mol) of boric
acid were used as initial batch in the glass vessel having a
double-walled jacket. A total of 229 g (2.32 mol) of gaseous
phosgene were introduced at from 1440 to 148.degree. C. over a
period of 5 hours with vigorous stirring. The system was then left
for a further hour without phosgene feed for subsequent reaction.
After stripping off the remaining, unconverted phosgene with
nitrogen a crude effluent weighing 310 g was obtained. The crude
effluent was fractionally distilled at from 70.degree. to
75.degree. C. and under a pressure of 0.7 kPa absolute (7 mbar
absolute). There were isolated 255 g of 5-chlorovaleric chloride
having a purity of >98 GC-areal %. This corresponds to a yield
of 82%.
Example 2 (Invention)
[0088] 172 g (2.0 mol) of .gamma.-butyrolactone, 9.3 g (0.1 mol) of
.beta.-picoline (3-methylpyridine) and 3.1 g (0.05 mol) of boric
acid were used as initial batch in the glass vessel having a
double-walled jacket and heated to 140.degree. C. A total of 242 g
(2.45 mol) of gaseous phosgene were introduced at from 140.degree.
to 147.degree. C. over a period of 4 hours and 15 minutes with
vigorous stirring. The system was then left for a further hour
without phosgene feed for subsequent reaction. After stripping off
the remaining, unconverted phosgene with nitrogen at 100.degree. C.
a crude effluent weighing 289 g was obtained. The crude effluent
contained 93.6 GC-areal % of 4-chlorobutyric chloride.
Example 3 (Invention)
[0089] 172 g (2 mol) of .gamma.-butyrolactone, 34.8 g (0.1 mol) of
Cyanex.RTM. 923 (commercial product sold by Cytec Industries and
comprising a mixture of various trialkyl phosphine oxides having an
average molecular weight of 348 g/mol) and 3.1 g (0.05 mol) of
boric acid were used as initial batch in the glass vessel having a
double-walled jacket. A total of 251 g (2.54 mol) of gaseous
phosgene were introduced at from 144.degree. to 148.degree. C. over
a period of 5 hours and 20 minutes with vigorous stirring. The
system was then left for a further hour without phosgene feed for
subsequent reaction. After stripping off the remaining, unconverted
phosgene with nitrogen at 100.degree. C. over a period of 7 hours a
crude effluent weighing 314 g was obtained. The crude effluent was
fractionally distilled at 87.degree. C. under a pressure of 5.1 kPa
absolute (51 mbar absolute). There were isolated 242 g of
4-chlorobutyric chloride having a purity of >99 GC-areal %. This
corresponds to a yield of 86%.
Example 4 (Invention)
[0090] 200 g (2.0 mol) of .delta.-valerolactone, 9.3 g (0.1 mol) of
.beta.-picoline (3-methylpyridine) and 5.2 g (0.05 mol) of
trimethyl borate were used as initial batch in the glass vessel
having a double-walled jacket and heated to 140.degree. C. A total
of 242 g (2.45 mol) of gaseous phosgene were introduced at from
140.degree. to 146.degree. C. with vigorous stirring. The system
was then left for a further hour without phosgene feed for
subsequent reaction. After stripping off the remaining, unconverted
phosgene with nitrogen at 100.degree. C. a crude effluent weighing
318 g was obtained. The crude effluent was fractionally distilled
at from 75.degree. to 77.degree. C. under a pressure of 0.9 kPa
absolute (9 mbar absolute). Following first runnings weighing 10 g,
which already contained 96.6 GC-areal % of 5-chlorovaleric
chloride, there was isolated a pure fraction weighing 256 g. It
contained 98.2 GC-areal % of 5-chlorovaleric chloride. The total
yield following distillation was 85%.
Example 5 (Invention)
[0091] 10 g (0.1 mol) of .delta.-valerolactone, 1.14 g (0.006 mol)
of benzyl-trimethylammonium chloride and 0.31 g (0.005 mol) of
boric acid were used as initial batch in the glass vessel having a
double-walled jacket. A total of 15.5 g (0.13 mol) of liquid
thionyl chloride were introduced at from 120.degree. to 125.degree.
C. over a period of 7 hours with vigorous stirring. The system was
then left for a further hour without thionyl chloride feed for
subsequent reaction. The effluent contained 70 GC-areal % of
5-chlorovaleric chloride and 7 GC-areal % of unconverted
.delta.-valerolactone.
Example 6 (Comparative Example)
[0092] 192 g (2.23 mol) of .gamma.-butyrolactone and 2 g (0.025
mol) of pyridine were used as initial batch in the glass vessel
having a double-walled jacket and heated to 120.degree. C. A total
of 60 g (0.61 mol) of gaseous phosgene were introduced at from
120.degree. to 124.degree. C. over a period of 8 hours with
vigorous stirring. After stripping off the remaining, unconverted
phosgene with nitrogen the crude effluent was fractionally
distilled. The first fraction weighing 76 g contained 21.6 GC-areal
% of 4-chlorobutyric chloride, the second fraction weighing 110 g
contained 2.6 GC-areal % of 4-chlorobutyric chloride. This
corresponds to a total yield of 6%.
[0093] Comparative Example 6 shows that in the absence of boron
compounds and without the introduction of hydrogen chloride only
insufficient yield can be attained.
* * * * *